Serious thought here, how would it be legal for the NHL to use replacement players to form a new league back up.

With out a Union to bargain a CBA with, pretty much all of the contracting rules the NHL uses or wants would be against US Law. Draft, term limits, Salary Cap, ELCs. They would not be able to uni-laterally install a CBA or rules for the replacement players without getting hammered by anti-trust lawsuits. McKinnon, Jones and Barkov? All to the highest bidder. It would be chaos and fantastic at the same time. Half the teams in the league would be bankrupt in 5 years cause teams can't contain themselves.

I have worked for businesses where the union and the business worked in concert together well to provide the best possible environment for both. The most realistic situation were something like this suggestion to happen is that the league would "plant" a new NHLPA, in order to "negotiate" terms, and maintain the salary cap, draft, etc.

The player-based league would never work. Think about the WHA for a second. Now think about how badly it failed. The NHL was 12 teams when the WHA was created; the WHA was just as big as the NHL team-wise. the NHL has 30 teams now, there's no way a "new WHA" could manage that many markets and have as much talent as the NHL. They couldn't even pay high-end European players; they'd be NHL or KHL still. Which leaves NA players. Maybe half as many teams if you can find ownership. And then you have to find markets. Where do they go? Balsillie probably gets in an puts one in Hamilton. Toronto, Montreal/Quebec, New York, Detroit, Seattle, Houston, Kansas City, where else?